1. Field of the Invention
The present invention relates to a pressure relief device.
2. Description of the Prior Art
Because of the energy crisis, every country tries to develop substitutes for petroleum, such as wind energy, solar energy, geothermal energy, tidal energy, and the like. In particular, wind energy doesn't have any pollution and is cost-effective. As shown in FIG. 1, a conventional wind power generator comprises a tower 1, a generator body 2 disposed on top of the tower 1, and a blade set 3 disposed at a front end of the generator body 2. The blade set 3 is driven to rotate by the wind, which then drives the generator body 2 to generate power such that the wind energy is converted into electric energy. The electric energy that can be generated by the wind power generator depends on the scale of the wind speed. When the wind speed is greater enough, the blade set 3 will be rotated faster. The generator body 2 may be burned out because of excessive rotations. Accordingly, an innovated wind power generator is provided with an automatic brake device. When the wind speed exceeds a predetermined value, the generator will slow down automatically or stop operation to achieve a protection effect. But, this automatic brake device cannot reduce the wind pressure which the blade set 3 bears. The blade of the wind power generator may be broken because of a greater scale of the wind speed, particularly in a place where a typhoon often happens. When the wind speed is increased, the wind power generator will be increasingly powered consequently. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to provide a pressure relief device which can reduce the wind pressure of a wind power generator.